Apparently, Red Bull has been using a loophole to get around their budget cap penalty and basically enjoy unlimited windtunnel time.
Due to a 'loophole' in the regulations, to state is simple, teams can run their car in the windtunnel as much as they want as long as it's for internal airflow (cooling etc.). During these runs, they aren't allowed to measure downforce levels, but that doesn't prevent them from learning about airflow as they can still visualize this and draw conclusions from about how to improve the aerodynamic surfaces.
The only constraint is the running costs of the windtunnel, as I think this has to be included in the budget cap?
Discuss!